Communication on short waves



y 1933. A. MEISSNER 1,917,312

COMMUNICATION ON SHORT WAVES Filed July 11, 1928 lllTiFvA/Wh IIMIMH 22Fifi/V52 HW/Sumvs Q0 Mil/VS A'CE/l/EQ 26 A ORNEY Patented July 11, 1933UNITED-STAT ALEXANDERMEISS ERQQE BERLIN, GERMANY, A's sIGNo ToTELEIEIJII'NKIEYN. Gnsnrn scHAr'r Fun nmnrrnosn 'rELEGnArHIE vr.

fRA'rIon or GERMANY ooMMunIoAmoN on snon'rwavns I npplication'filed July11,1928, Serial No- This invention relates to communication thatcommunication in an intelligible manner is greatly hampered bythepresence of fading phenomena. It has further been found that thefading is not simultaneously present in different simultaneouslytransmitted waves. It is" desirable for this reasontotransmitsimultaneously on two different wavelengths. :In practice, however, thisscheme would mean such a substantialincrease in' the cost ofequipmentthat such ..duplicate transmission methodhas heretofore notbeen used.

The present'inventi on represents a very considerable saving in cost. Inthe transmitter plants nowadays operated mostly on' the beam system, theantenna'plant is the most costly part of the station. In accordance withthe present invention, the antenna is so built and the wavesjof the twotransmitters are so chosen that two waves can be sent out simultaneouslywith one and the same antenna system. Experimental work shows that onlya very slight difierence in wave-length is needed to diminish the fading phenomena atthe receiver station. By the convenient and skilfuldisposition of the transmitters and the antenna, it is feasible, with aslight difference in the wave-lengths, to bring both transmitterssimultaneously to act upon one and the same directive antenna. Mutualinfluences between the two transmitters which, of course, are bound toarise, may

. then be eliminated by neutralization means between the transmitters.

Looked at from an economlcal viewpoint,

this novel arrangement is of particularly great value also for thereason that the operation is free from' extra energy losses. Whileheretofore it has beennecessary to provide a powerful transmitteradapted to send out a single wave and feed it to the antenna, the energyof the transmitter here disclosed is halved, and half-the total energymay be put into each wave. 1

29-13738; and in German m '28, 1927.

similar to that at the sending end may be employed, and in a similarmanner two receivers may be coupled with one and the same I antenna, thesame energy being brought to act by the addition or integration ofthe'two transmitting energies in the two receiver sys- E15 PTENT-OFFea-J B. or- BER I enmmngn c'oiaro .At the receiving 'end anantenna system t'ems, just as when working with one sender and oneantenna. p q

. The method is-particularly valuable'when the chief point'is' toadvantageouslylutilize elaborate directive spaceradiation antennae.

Theinvention is described in'conn'ection with the accompanying drawing,in-which Figure l is a transmitter, and

QFigure Q is arece1ver,=1n accordance with my inv.ention,jrepresented insimple form.

Referring to Figure 1 there aretwo transmitters, 1 and2, here. indicatedby way ofexample as each comprising an electron emission tube coupled toan oscillation circuit in,

three point connection. The oscillation circuits comprise not only theregenerative coupling coil and the tuning condensers, as is customary,but also include the coupling coils 4, which are coupled in such adirection as to oppose the coupling between the transmitters which wouldotherwise exist by rea-' sonof their both being'coupled to a singledirective short wave antenna 6. The tube anodes and controlelectrodesare provided I:

with suitable blocking condensers and choke coilsto separate the highfrequency and direct currents. Both transmitters are keyed by a singlekey 8, which serves to vary the bias on the control electrodes of thetubes by V applying thereto the potential of either the battery 10, orthe battery 12. It will be understood, of course, that in moreelaborate.

form the transmitters may comprise fre-i.

.quency controllingoscillators which govern the frequency'of poweramplifiers, in which case the keying may be accomplished at anyamplifier stage in the transmitters, as well as a at the oscillatoritself.

A receiver is indicated in simple form in Figure 2, and comprises adirective short wave receiving antenna 20, the energy collected fromwhich is supplied to receivers 22 and 24, tuned respectively to thefrequencies of the transmitters 1 and 2 in Figure 1 These modulatingboth of said energies simulta neously in accordance wlth -as1gnal be ngtransmitted, directively radiating both of the-modulated energies from asingle radiating point, and opposing said energies at the generationpoint to prevent the generation of energy of acsingle frequency. f

- 2.-The method vof communicating telegraphically with short wave energyWhich includes generating transmission energies of slightly 'diflerenthigh frequencies, simultaneously modulating said energies in accordanceWith a telegraphic signal, opposing saidenergies sufiiciently to preventthem from oscillating in synchronism, directively .radiatingthemodulated energies ata single point, directively collectingithe radiateden ergy at a single receivingpoint, separating the received frequencies,transforming-the received high frequency energies into translationenergies, combining the translation energies, and translating thecombined energy. 3. A transmlssion system comprising a first highfrequency. transmitter, a second.

high frequency transmitter tuned to a slightly d-ifi'erent highfrequency, means for simula .taneously modulating both of the transmis--sion energ es n accordance vvlth' a signal,

a directive antenna for radiating both of the modulated energies, meanscoupling the transmitters to the antenna, and means coupling thetransmitters in opposition to prevent them from oscillatinginsynchronism.

, 4. -A short Wave telegraph communication system comprising atransmission station having 'a'plurality of transmitters each tuned toslightly different high frequencies, :a single modulating means forsimultaneous.

lyj modulating each of said transmitters in accordance with atelegraphic signal,-a directive antenna, means coupling the transmittersto the antenna, means coupling the transmitters to eachother inopposition to oppose the mutual coupling caused loyv the antennacoupling, and a receiving station having a di- 5 rective receivingantenna, a, plurality of receivers tuned; to the transmissionfrequencies, means coupling the receivers to the receiving antenna, asmgletranslatlng device, and means coupling the translating device tothe receivers. a

q ALEXANDER MEISSN'ERQ

